A number of devices are known in the prior art for drying wet paper webs during manufacture of the paper webs. One well known device for drying wet paper webs is the yankee dryer which incorporates a heated drum carrying the wet paper web through the interior of a hood operatively associated therewith. The interior of the hood contains heated air which circulates through the hood and contacts the outer surface of the paper web. In conventional yankee dryers the air is heated at a location exterior of the hood.
A search directed to the present invention located the following United States patents: U.S. Pat. No. 2,268,988, issued Jan. 6, 1942, U.S. Pat. No. 3,163,502, issued Dec. 29, 1964, and U.S. Pat. No. 3,377,056, issued Apr. 9, 1968.
U.S. Pat. No. 3,377,056 discloses a hood having a main housing and sub-housings on either side thereof. Cooling and heating components are located in the sides of the housing. Burners are provided in the walls of plenum chambers for heating the air supplied to the paper web positioned on a yankee dryer drum.
U.S. Pat. No. 2,268,988 discloses a manifold disposed about a drum. Burners are positioned about the circumference of the drum in order to heat ink which is positioned on paper transported around the outer surface of the drum.
U.S. Pat. No. 3,163,502 is directed to a removable hood for drying a web of material conveyed around cylinders. Heating ducts are provided in each of the hood sections. Gas heated by a fire tube may be substituted for the heater ducts. The ducts are essentially identical and each provides a passage at opposite ends communicating with the exhaust air chamber.